In hermetic compressors, the problem exists of an electric connection and an accompanied electrical feed-through leading through a casing of the hermetic compressor combined with the problem of pressure tightness of the feed-through, as there is a pressure difference between an interior of the casing and an outside environment.
Therefore, appropriately pressure-tight feed-throughs, which at the same time electrically insulate against the compressor casing, are needed.
Various types of insulating and pressure-tight casing feed-throughs are known, particularly for the connection of HVAC compressors.
Typically, electrical casing feed-throughs are established as insulation members made of glass or ceramic combined with sealing elements such as O-rings or flat gaskets. An electrically conductive connecting or conductor pin(s) is passed through the insulation member made of glass or ceramic. Sealing between the conductor pin and the insulation member is problematic.
In certain embodiments, a metal sleeve typically encloses the insulation member and is arranged in an opening of the casing. An additional elastic seal ensures sealing of the conductor feed-through against the casing.
In U.S. Pat. No. 6,362,424 B1, a conductor feed-through is disclosed, referred to as hermetic connection assembly. The disadvantages of the prior art feed-through are the problematic sealing of the glass/metal-connection, due to the different expansion coefficients, for example, and the fragility of glass or ceramic when mechanically loaded.
To overcome the disadvantages of U.S. Pat. No. 6,362,424 B1, German Pat. No. DE 33 24 466 C2 proposes to create sealing by use of an insulation member made of a flexible material such as elastomers or thermoplastics. The solution proposed in German Pat. No. DE 33 24 466 C2 is disadvantageous in that no permanent sealing between the conductor pin and the flexible insulation member is ensured. In addition, assembling must be executed very cautiously and carefully to prevent the conductor pins and the opening that accepts the conductor pins from being damaged.
Accordingly, it is desirable to develop an electrical conductor feed-through capable of being connected to a casing in an electrically insulated and pressure-tight manner as well as withstanding mechanical loads and temperatures of about 150° C. A solution is also to be designed to consist of as few as possible components and to be capable of being easily mounted and produced at low cost.